They Can't See As Clearly As They Think

"Anton syndrome: maybe not the scariest but definitely still very strange and distressing."

"Essentially you get bilateral visual cortex strokes (with some parietal cortex damage), so you’re completely blind."

"But you don’t know you’re blind."

"These people will swear on their mother’s grave that they can see, but then walk straight into a wall."

"Imagine going the rest of your life genuinely believing you can see, despite constantly being told otherwise."- Spiritual-Gap3695·

A Living Statue

"Fibrodysplasia ossificans progressiva."

"Your muscles and tendons slowly turn to bone rendering you immobile, in constant pain due to pinched nerves, and unable to speak or eat."

"You basically just become a fully sentient statue that is in constant agony."- ky1esty1e

Too Many To Choose From...

"fibrodysplasia ossificans progressiva."

"Slowly turn into bone."

"Towards the end you have to choose whether you want to be laying down or sitting."

"Fatal insomnia."

"You can either get the generic kind or the random kind."

"Either way you will never sleep again."

"I’m also partial to Ebola and Prion diseases."

"Shout out also to alien hand syndrome, cotard delusion, capgras delusion, visual agnosia, and koro."

"Also, there is a special kind of hell for Alzheimer’s and Lewy Body dementia."- TheRealDannySugar

Why You Must Stay Up To Date On Vaccines!

"The extreme clenching of every muscle in your body until your teeth shatter, bones break, and your body constricts itself to death."

"We are constantly reminded of this disease, but with vaccination and modern medicine, people are mostly unaware of how horrible it can be outside of historical and medical texts."

"Tetanus."- Gr4ph0n

It Affects More People Than You Think

'ALS (amyotrophic lateral sclerosis) also known as Lou Gehrig’s disease."

"Or any neurodegenerative disease, for that matter."- NuMD97

Thank Goodness For Modern Science

"Despite the fact that we have a vaccine for it, I have been absolutely petrified of diphtheria since reading 'The Cruelest Miles.'"

"Without treatment, the thought of slowly choking to death on mucus membranes covering your lymph nodes... terrifying."- GlowCavern

Manifesting Slowly

"I’m gonna go with prion diseases."

"They can hang out in your body for decades before causing symptoms, have no known treatments, and are very difficult to destroy."

"I’m also personally uncomfortable with the idea of proteins in my body misfolding."

"My nightmare scenario is a CWD becoming transmissible to humans."- Mirrorflute88

'Biologist - prion disease is terrifying."

"They're a kind of protein that is the 'wrong way' ( think mirror image) and other proteins they encounter mimic them."

"So a healthy normal protein encounters an abnormally folded prion and re-folds itself the way the prion is folded."

"This creates a chain reaction and results in neurodegeneration and encephalopathy (holes in the brain)."

"Think mad cow disease (aka, Creutzfeldt-Jakob disease CJD)."

"It is always fatal and is contracted by eating brain/neural tissue)."

"F*cking terrifying."- ticklewhales

The Dreaded C-Word

"Resident doctor here."

"A terrifying type of illness I haven't seen mentioned yet are head and neck cancers in general."

"They tend to have a terrible quality of life they can have due to masses pushing into their airways or esophagus."

"Had a patient not long ago with a kind of throat cancer caused by HPV which led his bottom teeth needing to be removed and not being able to eat solid food."- Reddit

Hang On To Those Memories

"I would say Alzheimer's."

"Imagine forgetting everything and everyone you loved."

"Imagine slowly forgetting how to do things, how to walk, eat, drink and talk."

"Eventually you die because you forget how to breathe."

"To me that's pretty horrifying, and think of the family members who see them going through that!"- InFiniTeDEATH8

No Known Antidote

"I’m not sure if this is considered a disease but I would say radiation poisoning could be the worst."

"Depending on isotope and the level of exposure radiation can do some absolutely twisted sh*t to the human body."- S0M3D1CK

Only One Thing On the Menu For Them...

"Flesh eating is just as f*cked up as all the rest , you never know if its all cut-out or not until it f*cking eats your leg."- gotbetterbro

Trapped In Your Own Body

"Locked-in syndrome."

'You’re cognitively there, but you cannot move any part of your body."- Softconcrete579

Talk About Skin Crawling

"Surprised no one has mentioned pemphigus."

"It is extremely rare, but it is it an awful way to go."

"Schwarzschild died of it, you know, the guy that calculated the 'Schwarzschild radius'."

"Yeah, turns out you haven't heard of him for anything else in physics was his early, horrifying demise to pemphigus." -Reddit

Depends On The Circumstances

"Without modern medicine: plague making your blood septic and rotten."

"Without knowledge of what is happening: rabies."

"Without the support of others: alzheimers."- cherrycoloredcheeks

Perhaps the most frightening thing about all these bone-chilling diseases and illnesses?

They could happen to literally anyone.